Image forming apparatus and control method

Abstract

To form images with different glossiness on one recording medium.SOLUTION: An image formation apparatus 1 forms a nip 45 between a heating rotor 41 and a pressure rotor 42, and heats and presses a recording medium 11 transferred with toner 39 and conveyed in the nip 45 to fix the toner 39 to the recording medium 11. The image formation apparatus 1 includes a glossiness adjustment mode of forming and outputting the image with the changed glossiness within the same plane of the recording medium 11 by changing the relative speed of the heating rotor 41 and the pressure rotor 42 while the recording medium 11 is passing through the nip 45.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and a control method, and more particularly to a technique for adjusting the glossiness of an image formed on a recording medium such as printing paper. [Background technology]

[0002] An image forming apparatus that forms an image on a recording medium such as printing paper using an electrophotographic method is equipped with a fixing section that forms a nip between a heating roller and a pressure roller, and applies heat and pressure treatment to the recording medium onto which toner has been transferred and which has been transported as it passes through the nip between the heating roller and the pressure roller, thereby fixing the toner to the recording medium.

[0003] In the past, in this type of image forming apparatus, a glossiness test mode has been proposed in which, before forming an image to be printed on a recording medium, the glossiness of the image actually formed on the recording medium can be adjusted in advance (for example, Patent Document 1). In this prior art, in the glossiness test mode, multiple sets of toner images with image gradation patterns in which the image gradation gradually changes are formed on the same surface of a single recording medium, and when the recording medium passes through a fixing section, the heating temperature of the heating roller is changed so that it becomes a different temperature for each set of image gradation patterns, thereby forming fixed images with different glossiness on a single recording medium. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-219444 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it is difficult to change the heating temperature of the heating roller while the recording medium is passing through the fixing section. Generally, because heating rollers have poor thermal response, even if the heater temperature (heat source) is changed, it takes a certain amount of time for the surface temperature of the heating roller to change. Therefore, even if an attempt is made to change the surface temperature of the heating roller to a different temperature for each set of image gradation patterns while the recording medium is passing through the nip between the heating roller and the pressure roller, it is difficult to achieve this. Therefore, with the above-mentioned conventional technology, it is difficult to form fixed images with different gloss levels on a single recording medium.

[0006] Therefore, the present invention has been made to solve the above-mentioned conventional problems, and aims to provide an image forming apparatus and a control method that are capable of forming images with different gloss levels on a single recording medium. [Means for solving the problem]

[0007] In order to achieve the above object, the invention according to claim 1 is an image forming apparatus that forms a nip between a heating rotator and a pressure rotator, and heats and pressurizes a recording medium onto which toner has been transferred and conveyed at the nip, thereby fixing the toner to the recording medium, and has a glossiness adjustment mode that changes the relative speed between the heating rotator and the pressure rotator while the recording medium is passing through the nip, thereby forming and outputting an image with a varying glossiness on the same surface of the recording medium. The gloss level adjustment mode is a mode in which the relative speed between the heating rotor and the pressure rotor is continuously changed. The configuration is characterized by the above.

[0009] Claim 2 The invention according to claim 1 In the image forming apparatus of the present invention, the gloss level adjustment mode is characterized in that the speed of the pressure rotating member is kept constant and the speed of the heating rotating member is changed.

[0010] Claim 3 The invention relates to: An image forming apparatus in which a nip is formed between a heating rotor and a pressure rotor, and a recording medium onto which toner has been transferred and which is conveyed is heated and pressurized at the nip, thereby fixing the toner to the recording medium, the image forming apparatus having a glossiness adjustment mode in which, while the recording medium is passing through the nip, a relative speed between the heating rotor and the pressure rotor is changed, thereby forming and outputting an image with a varying glossiness on the same surface of the recording medium; In the gloss level adjustment mode, the speed of the pressure rotating body is set to the conveying speed of the recording medium. Constant at retention and changing the speed of the heating rotor. The configuration is characterized by the above.

[0011] Claim 4 The invention relates to: An image forming apparatus in which a nip is formed between a heating rotator and a pressure rotator, and a recording medium onto which toner has been transferred and which is conveyed is heated and pressurized at the nip, thereby fixing the toner to the recording medium, An image forming section that transfers the toner onto the recording medium. a glossiness adjustment mode in which, while the recording medium is passing through the nip, a relative speed between the heating rotor and the pressure rotor is changed, thereby forming and outputting an image with a varying glossiness within the same surface of the recording medium, The image forming unit is configured to form an image of the same density along the conveyance direction of the recording medium in the gloss level adjustment mode.

[0012] Claim 5 The invention according to claim 4 In the image forming apparatus, the image forming unit is configured to print identification information indicating the glossiness along the transport direction of the recording medium when forming an image of the same density on the recording medium.

[0013] Claim 6 The invention according to claim 5 The image forming apparatus is provided with a control unit that sets the gloss level when a print job is executed, and when the identification information printed on the recording medium is specified by a user, the control unit sets the gloss level when the print job is executed based on the specified identification information.

[0014] Claim 7 The invention according to claim 6 In the image forming apparatus, in the gloss level adjustment mode, the apparatus further comprises a memory unit that stores speed information of the heating rotor and the pressure rotor when the identification information passes through the nip in association with the identification information, and when the identification information printed on the recording medium is specified by a user, the control unit reads out the speed information associated with the specified identification information from the memory unit and sets the speed when the print job is executed.

[0015] Claim 8 The invention according to claim 7In the image forming apparatus, the memory unit stores characteristic information indicating the characteristics of the recording medium used in the gloss adjustment mode in further correspondence with the identification information, and the control unit sets the speed when the print job is executed based on the speed information read from the memory unit when the characteristics of the recording medium used when the print job is executed match the characteristics of the recording medium indicated by the characteristic information.

[0016] Claim 9 The invention relates to a method for controlling an image forming apparatus that forms a nip between a heating rotator and a pressure rotator, and heats and pressurizes a recording medium onto which toner has been transferred and conveyed at the nip, thereby fixing the toner to the recording medium. The method operates the image forming apparatus in a glossiness adjustment mode that forms and outputs an image with varying glossiness on the same surface of the recording medium by changing the relative speed between the heating rotator and the pressure rotator while the recording medium is passing through the nip. In the gloss level adjustment mode, the relative speed between the heating rotor and the pressure rotor is continuously changed. The configuration is characterized by the above.

[0018] Claim 10 The invention according to claim 9 In the control method of (1), in the gloss level adjustment mode, the speed of the pressure rotating body is kept constant and the speed of the heating rotating body is changed.

[0019] Claim 11 The invention relates to: A control method for an image forming apparatus that forms a nip between a heating rotor and a pressure rotor, and heats and pressurizes a recording medium, onto which toner has been transferred and conveyed, at the nip, thereby fixing the toner to the recording medium, the method comprising: operating the image forming apparatus in a glossiness adjustment mode in which, while the recording medium is passing through the nip, a relative speed between the heating rotor and the pressure rotor is changed, thereby forming and outputting an image with a varying glossiness within the same surface of the recording medium; In the gloss level adjustment mode, the speed of the pressure rotating body is set to the conveying speed of the recording medium. constant at held in and changing the speed of the heating rotor. The configuration is characterized by the above.

[0020] Claim 12 The invention relates to: A control method for an image forming apparatus that forms a nip between a heating rotor and a pressure rotor, and heats and pressurizes a recording medium, onto which toner has been transferred and conveyed, at the nip, thereby fixing the toner to the recording medium, the method comprising: operating the image forming apparatus in a glossiness adjustment mode in which, while the recording medium is passing through the nip, a relative speed between the heating rotor and the pressure rotor is changed, thereby forming and outputting an image with a varying glossiness within the same surface of the recording medium; In the gloss level adjustment mode, an image with the same density is formed along the conveyance direction of the recording medium.

[0021] Claim 13 The invention according to claim 12In the control method of the above, when an image of the same density is formed on the recording medium, identification information indicating the glossiness is printed along the conveyance direction of the recording medium.

[0022] Claim 14 The invention according to claim 13 In the control method, when the identification information printed on the recording medium is specified by a user, the gloss level at the time of executing the print job is set based on the specified identification information.

[0023] Claim 15 The invention according to claim 14 In the control method of the present invention, in the gloss level adjustment mode, speed information of the heating rotor and the pressure rotor when the identification information passes through the nip is stored in a predetermined memory unit in association with the identification information, and when the identification information printed on the recording medium is specified by a user during execution of a print job, the speed information associated with the specified identification information is read from the memory unit, and the speed setting during execution of the print job is performed.

[0024] Claim 16 The invention according to claim 15 In the control method of the present invention, characteristic information indicating the characteristics of the recording medium used in the gloss adjustment mode is further associated with the identification information and stored in the memory unit, and when the characteristics of the recording medium used when executing a print job match the characteristics of the recording medium indicated by the characteristic information, the speed setting when executing the print job is performed based on the speed information read from the memory unit. [Effects of the Invention]

[0025] According to the present invention, images with different gloss levels can be formed on a single recording medium more simply and reliably than ever before. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 illustrates an example of the configuration of an image forming apparatus. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a fixing unit. [Figure 3] 10 is a diagram showing the relationship between the relative speed of the heating roller and the pressure roller and the glossiness of an image formed on a recording medium. [Figure 4] 10A and 10B are diagrams illustrating examples of toner images transferred onto a recording medium in a gloss level adjustment mode. [Figure 5] 10A and 10B are diagrams illustrating examples of recording media output from an image forming apparatus in a gloss level adjustment mode. [Figure 6] FIG. 10 is a diagram showing the relationship between identification information, glossiness, and relative speed. [Figure 7] FIG. 10 is a diagram showing the relationship between gloss and the speed of a heating roller. [Figure 8] FIG. 10 is a diagram illustrating an example of a tray setting screen. [Figure 9] FIG. 10 is a diagram illustrating an example of tray information. [Figure 10] FIG. 10 is a diagram showing an example of a screen when a gloss level adjustment mode is executed. [Figure 11] FIG. 10 is a diagram showing an example of a screen when a gloss level adjustment mode is executed. [Figure 12] 10 is a flowchart illustrating an example of a processing procedure by a control unit when a gloss level adjustment mode is executed. [Figure 13] 10 is a flowchart illustrating an example of a processing procedure by a control unit when a gloss level adjustment mode is executed. [Figure 14] FIG. 10 is a diagram illustrating an example of information stored in a storage unit during execution of a gloss level adjustment mode. [Figure 15] FIG. 10 is a diagram showing an example of recording medium information. [Figure 16] 10 is a flowchart illustrating an example of a processing procedure performed by a control unit when a print job is executed. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Elements common to the embodiments described below are designated by the same reference numerals, and redundant description thereof will be omitted.

[0028] (Embodiment) 1 is a diagram showing an example of the configuration of an image forming apparatus 1 according to one embodiment of the present invention. This image forming apparatus 1 is configured as an MFP equipped with multiple functions, such as a copy function, a scan function, and a print function, and has a printer unit 1a provided at the bottom of the apparatus body and a scanner unit 1b provided at the top of the apparatus body. The image forming apparatus 1 also has an operation panel 5 above the printer unit 1a. Furthermore, the image forming apparatus 1 has a control unit 7 inside the apparatus body that controls the operation of each unit.

[0029] Printer unit 1a uses sheet materials such as printing paper, envelopes, etc. as recording medium 11, and forms an image on recording medium 11 by electrophotography. For example, printer unit 1a operates when a copy job or a print job is executed in image forming apparatus 1. Then, printer unit 1a transfers a toner image based on image data to be printed onto recording medium 11, fixes the toner image on recording medium 11, and outputs the image.

[0030] The scanner unit 1b optically reads an image of a document set by a user and generates an image. The scanner unit 1b may have a known configuration.

[0031] The operation panel 5 is a user interface when a user uses the image forming apparatus 1, and includes a display unit 6 that displays various operation screens. The control unit 7 also includes a control unit 8 and a storage unit 9. For example, the control unit 8 has a hardware configuration including a CPU and memory (not shown), and controls the operation of each unit by executing a computer-readable program. The storage unit 9 is a non-volatile storage device such as a hard disk drive (HDD) or solid-state drive (SSD), and various pieces of information are written to and read from the storage unit 9 by the control unit 8.

[0032] As shown in FIG. 1, the printer unit 1a includes a paper feed unit 2, an image forming unit 3, and a fixing unit 4.

[0033] The paper feed unit 2 includes multiple trays 10a and 10b. The multiple trays 10a and 10b accommodate recording media 11. The recording media 11 accommodated in each tray 10a and 10b may be the same or different types. The paper feed unit 2 feeds the recording media 11 from one of the multiple trays 10a and 10b designated by the user. The paper feed unit 2 includes a pickup roller 12 that contacts the topmost recording medium 11 of the stack of recording media 11 accommodated in each tray 10a and 10b. The paper feed unit 2 drives the pickup roller 12 of the tray designated by the user to feed one sheet of recording media 11 toward a downstream conveyance path 14. The conveyance path 14 for the recording media 11 includes a conveyance roller 13 and a timing roller 15. When driving the pickup roller 12, the paper feed unit 2 also drives the downstream conveyance roller 13 to convey the recording media 11 along the conveyance path 14. When the leading edge of the recording medium 11 reaches the timing roller 15, the conveyance of the recording medium 11 is temporarily stopped. A secondary transfer roller 16 is provided downstream of the timing roller 15.

[0034] The image forming unit 3 includes multiple image forming units 3Y, 3M, 3C, and 3K that form toner images of yellow (Y), magenta (M), cyan (C), and black (K), respectively, and an intermediate transfer belt 20. Each of the multiple image forming units 3Y, 3M, 3C, and 3K has the same structure, differing only in the color of the toner that is primarily transferred to the intermediate transfer belt 20. Specifically, each image forming unit 3Y, 3M, 3C, and 3K includes a cylindrical photoreceptor 30, a charging unit 31, an exposure unit 32, a developing unit 33, a primary transfer roller 34, and a cleaning unit 35. The intermediate transfer belt 20 is an endless belt. The intermediate transfer belt 20 is stretched over a drive roller 21, a ground roller 22, a tension roller 23, and a driven roller 24. When the drive roller 21 is rotated, the intermediate transfer belt 20 moves in a circular motion in the direction indicated by the arrow in the figure. The tension roller 23 applies a constant tension to the intermediate transfer belt 20. The intermediate transfer belt 20 is sandwiched between the earth roller 22 and the secondary transfer roller 16 .

[0035] The photoconductor 30 is positioned adjacent to the circulating intermediate transfer belt 20 and rotates in the direction indicated by the arrow in the figure. A charging unit 31, an exposure unit 32, a developing unit 33, a primary transfer roller 34, and a cleaning unit 35 are arranged around the photoconductor 30. The charging unit 31 charges the surface of the photoconductor 30 to a predetermined charge. The exposure unit 32 exposes the surface of the photoconductor 30, which has been charged to a predetermined charge, with laser light or the like to form an electrostatic latent image on the surface of the photoconductor 30. The developing unit 33 applies a developer containing toner to the surface of the photoconductor 30, thereby visualizing the electrostatic latent image with toner. The primary transfer roller 34 is positioned opposite the photoconductor 30 across the intermediate transfer belt 20. The intermediate transfer belt 20 is brought into contact with the surface of the photoconductor 30, and the toner image formed on the surface of the photoconductor 30 is primarily transferred to the intermediate transfer belt 20.

[0036] Each of the image forming units 3Y, 3M, 3C, and 3K performs primary transfer so that the toner images of each color are superimposed on the intermediate transfer belt 20, thereby forming a color image on the intermediate transfer belt 20. The intermediate transfer belt 20 on which the color image has been formed then moves in a circular motion and is guided between the secondary transfer roller 16 and the earth roller 22.

[0037] The paper feed unit 2 temporarily stops the transport of the recording medium 11 when the leading edge of the recording medium 11 reaches the timing roller 15, and then drives the timing roller 15 to coincide with the timing at which the toner image primarily transferred onto the intermediate transfer belt 20 reaches the position of the secondary transfer roller 16, thereby transporting the recording medium 11 toward the secondary transfer roller 16. This causes the timing at which the recording medium 11 reaches the secondary transfer roller 16 to coincide with the timing at which the toner image primarily transferred onto the intermediate transfer belt 20 reaches the secondary transfer roller 16. As a result, the toner image primarily transferred onto the intermediate transfer belt 20 comes into contact with the surface of the recording medium 11 as it passes the position of the secondary transfer roller 16. A predetermined potential is applied to the secondary transfer roller 16, and the toner image primarily transferred onto the intermediate transfer belt 20 is secondarily transferred onto the surface of the recording medium 11 by the electrostatic force of the secondary transfer roller 16.

[0038] The recording medium 11 onto which the toner image has been secondarily transferred by the secondary transfer roller 16 is then transported to the fixing unit 4. The fixing unit 4 is equipped with a heating rotator 41 and a pressure rotator 42, and applies heat and pressure to the recording medium 11 onto which the toner image has been transferred, thereby fixing the toner to the recording medium 11. The recording medium 11 is then discharged onto a paper discharge tray 19 formed on the side of the device body by a transport roller 17 and a discharge roller 18.

[0039] Fig. 2 is a diagram showing an example of the configuration of the fixing unit 4. As shown in Fig. 2, the heating rotator 41 and the pressure rotator 42 come into contact with each other to form a nip 45. The fixing unit 4 is configured to sandwich the recording medium 11, which has the toner 39 transferred thereon, in the nip 45 between the heating rotator 41 and the pressure rotator 42, and perform a heating process and a pressure process.

[0040] For example, the heating rotator 41 in this embodiment is constituted by a heating roller 43. For example, the heating roller 43 has a cylindrical core 431 made of aluminum or the like, on the surface of which a heat-resistant elastic layer 432, which is an elastic body, is formed, and the outer peripheral surface of the heat-resistant elastic layer 432 is further coated with a release layer 433. The heating roller 43 has a rotation shaft 43a in its center. The rotation shaft 43a is driven to rotate in a predetermined direction by a driving unit 48 such as a motor, thereby rotating the heating roller 43 in a predetermined direction. The rotation direction of the heating roller 43 is clockwise in FIG. 2. A heat source 46, such as a halogen heater, is provided inside the heating roller 43. The heat source 46 is controlled by the control unit 8 to heat the surface temperature of the heating roller 43 to a predetermined temperature.

[0041] Furthermore, the pressure rotor 42 in this embodiment is constituted by a pressure roller 44. For example, the pressure roller 44 has a configuration in which a heat-resistant elastic layer 442 made of silicone rubber is formed on the surface of a cylindrical core metal 441 made of aluminum or the like, and a coating layer 443 made of fluororesin is further formed on the surface of the heat-resistant elastic layer 442. The pressure roller 44 has a rotation shaft 44a in its center. The rotation shaft 44a is rotated in a predetermined direction by a drive unit 49 that is different from the drive unit 48 of the heat roller 43, thereby rotating the pressure roller 44 in the predetermined direction. The rotation direction of the pressure roller 44 is counterclockwise in FIG. 2.

[0042] One end of a support member 51 is attached to the rotation shaft 44a of the pressure roller 44. The other end of the support member 51 is attached to a rotation shaft 52 provided in the device body. Therefore, the support member 51 can swing around the rotation shaft 52 as a fulcrum and supports the pressure roller 44 at its tip. An elastic member 53 such as a spring is attached to the support member 51. This elastic member 53 presses the support member 51 upward. An eccentric cam 54 is attached to the support member 51 in contact with the opposite side of the elastic member 53. The eccentric cam 54 is rotatable around the rotation shaft 54a and presses the support member 51 downward according to the rotation angle. Therefore, the control unit 8 can adjust the pressure contact force of the pressure roller 44 against the heating roller 43 by adjusting the angular position of the eccentric cam 54.

[0043] The image forming apparatus 1 configured as described above has a glossiness adjustment mode in addition to a normal operation mode in which a normal print job or the like is executed, and can operate in the glossiness adjustment mode. The glossiness adjustment mode is an operation mode in which images with different glossiness levels are formed and output on a single recording medium 11. For example, if the type or basis weight of the recording medium 11 fed from the paper feed unit 2 changes, the glossiness of the image formed on the recording medium 11 also changes. Therefore, the glossiness adjustment mode is executed, for example, when a new recording medium 11 is set in tray 10a or 10b. By executing the glossiness adjustment mode, the glossiness of the image formed on the new recording medium 11 can be adjusted in advance to the glossiness desired by the user.

[0044] In the gloss level adjustment mode, the control unit 8 feeds one sheet of recording medium 11 from the tray 10a or 10b specified by the user, and transfers a toner image of a predetermined pattern onto that sheet of recording medium 11. Then, when the recording medium 11 onto which the toner image of the predetermined pattern has been transferred passes through the fixing unit 4, the control unit 8 controls the operation of the fixing unit 4 to form an image with a varying gloss level on the surface of the recording medium 11.

[0045] In the fixing unit 4 described above, the heating roller 43 and the pressure roller 44 are driven by separate driving units 48 and 49. In the gloss adjustment mode, the control unit 8 changes the relative speed between the heating roller 43 and the pressure roller 44 while the recording medium 11 is passing through the nip 45 between the heating roller 43 and the pressure roller 44, thereby forming an image with varying glossiness on the same surface of the recording medium 11.

[0046] With the recording medium 11 sandwiched in the nip 45 between the heating roller 43 and the pressure roller 44, the heating roller 43 heats and melts the toner 39 transferred to the surface of the recording medium 11, and then compresses the melted toner 39 to fix it to the recording medium 11. At this time, the wax component contained in the toner 39 spreads over the surface of the recording medium 11, imparting gloss to the image. If the wax component spreads widely, the glossiness of the image increases. Conversely, if the wax component spreads little, the glossiness of the image decreases. Focusing on this point, in this embodiment, an image with varying glossiness is formed on the same surface of the recording medium 11 by changing the relative speed between the heating roller 43 and the pressure roller 44.

[0047] FIG. 3 is a diagram showing the relationship between the relative speed Vs of the heating roller 43 and the pressure roller 44 and the glossiness of the image formed on the recording medium 11. In FIG. 3, when the speed of the heating roller 43 is V1 and the speed of the pressure roller 44 is V2, the relative speed Vs is expressed as Vs = V1 - V2. As shown in FIG. 3, the glossiness of the image formed on the recording medium 11 changes along the characteristic line Ts as the relative speed Vs changes. That is, when the speed V1 of the heating roller 43 and the speed V2 of the pressure roller 44 are equal and the relative speed Vs of the heating roller 43 and the pressure roller 44 is 0, the glossiness of the image formed on the recording medium 11 is Dg. In contrast, when the speed V1 of the heating roller 43 is greater than the speed V2 of the pressure roller 44, the glossiness of the image formed on the recording medium 11 exceeds Dg. The glossiness gradually increases as the difference between the speed V1 of the heating roller 43 and the speed V2 of the pressure roller 44 increases. Conversely, when the speed V1 of the heating roller 43 is slower than the speed V2 of the pressure roller 44, the glossiness of the image formed on the recording medium 11 falls below Dg, and the glossiness gradually decreases as the difference between the speed V1 of the heating roller 43 and the speed V2 of the pressure roller 44 increases. For example, in the glossiness adjustment mode, the control unit 8 continuously changes (increases or decreases) the relative speed Vs between the heating roller 43 and the pressure roller 44 while the recording medium 11 to which the toner 39 has been transferred passes through the nip 45, thereby forming an image whose glossiness continuously changes as shown in FIG.

[0048] FIG. 4 is a diagram illustrating a toner image of a predetermined pattern transferred to the recording medium 11 in the gloss adjustment mode. In the gloss adjustment mode, the control unit 8 controls the image forming unit 3 to transfer an image (toner image) of a predetermined pattern as shown in FIG. 4 onto the recording medium 11. That is, images of long rectangular patterns of the respective colors Y, M, C, and K are transferred onto the surface of the recording medium 11. Here, the longitudinal direction of the images of each color (the left-right direction in FIG. 4) coincides with the transport direction of the recording medium 11. Furthermore, the images of each color are images of the same density in the transport direction of the recording medium 11. Furthermore, the images of each color are formed at the same position in the transport direction of the recording medium 11 and have the same length.

[0049] The control unit 8 also transfers identification information 38, which indicates different gloss levels along the longitudinal direction of the image for each color, onto the recording medium 11 at positions adjacent to the image of the elongated rectangular pattern for each color. FIG. 4 illustrates an example in which the numbers "1" to "8" are transferred as the identification information 38 from one end of the image to the other. Each of these numbers is the identification information 38 indicating the gloss level. However, the identification information 38 is not necessarily limited to numbers, and may also use letters, symbols, or the like. Therefore, the recording medium 11 that has passed through the secondary transfer roller 16 in the gloss adjustment mode has an image such as that shown in FIG. 4 transferred onto its surface.

[0050] When the leading edge of recording medium 11 shown in FIG. 4 reaches nip 45 between heating roller 43 and pressure roller 44 of fixing unit 4, control unit 8 continuously changes the relative speed Vs between heating roller 43 and pressure roller 44. For example, control unit 8 may gradually decrease relative speed Vs from a state in which it has increased to a predetermined value, or conversely, may gradually increase relative speed Vs from a state in which it has decreased to a predetermined value. Furthermore, control unit 8 preferably controls relative speed Vs continuously from the time the leading edge of the image of the elongated rectangular pattern of each color transferred to recording medium 11 reaches nip 45 to the time the trailing edge of the image exits nip 45. By performing such control, the glossiness of the image of the elongated rectangular pattern of each color transferred to recording medium 11 continuously changes along the conveyance direction of recording medium 11 as it passes through fixing unit 4.

[0051] Furthermore, the control unit 8 stores the position where the identification information 38 is transferred onto the recording medium 11, and stores in the memory unit 9 speed information relating to the speeds V1 and V2 of the heating roller 43 and the pressure roller 44 when the identification information 38 transferred onto the recording medium 11 passes through the nip 45. At this time, the control unit 8 stores the speed information in the memory unit 9 in association with the identification information 38 passing through the nip 45. As a result, when the gloss level adjustment mode is terminated, if the identification information 38 is designated, it becomes possible to specify the speeds V1 and V2 of the heating roller 43 and the pressure roller 44 when the identification information 38 passed through the nip 45.

[0052] FIG. 5 is a diagram illustrating a recording medium 11 output in the gloss adjustment mode. When the recording medium 11, onto which an image of a long rectangular pattern with the same density for each color has been transferred, passes through the fixing unit 4, the relative speed Vs between the heating roller 43 and the pressure roller 44 continuously changes, resulting in an image in which the glossiness of the image of the long rectangular pattern changes along the conveyance direction of the recording medium 11, as shown in FIG. 5. Furthermore, the recording medium 11 is provided with identification information 38 attached adjacent to the image of the long rectangular pattern in a state where the glossiness has changed. Therefore, by checking the recording medium 11 as shown in FIG. 5, the user can specify the desired glossiness based on the identification information 38. In other words, the identification information 38 attached to the recording medium 11 serves as an index for specifying the glossiness.

[0053] FIG. 6 is a diagram showing the relationship between the identification information 38, the gloss level, and the relative speed Vs. In the example shown in FIG. 6, as the relative speed Vs between the heating roller 43 and the pressure roller 44 increases, the gloss level of the image increases, and the value of the identification information 38 attached to the recording medium 11 also increases. Therefore, if a user determines that the gloss level they desire corresponds to the gloss level corresponding to the identification information 38 "6," they can specify the gloss level by inputting the identification information "6" into the image forming apparatus 1. Furthermore, the control unit 8 can identify the gloss level desired by the user based on the identification information 38 specified by the user, and can control the operation of the fixing unit 4 to achieve that gloss level when executing a print job.

[0054] As described above, the pressure roller 44 contacts the back side of the recording medium 11 and primarily functions to transport the recording medium 11 downstream in the transport direction as it passes through the nip 45. Therefore, it is preferable to set the speed V2 of the pressure roller 44 to the process speed of the image forming apparatus 1, which matches the transport speed of the recording medium 11 when transporting the recording medium 11 from the paper feed unit 2 to the paper output tray 19. Therefore, when forming images with different gloss levels on a single recording medium 11 in the gloss level adjustment mode, the control unit 8 of this embodiment is configured to maintain the speed V2 of the pressure roller 44 at the process speed and change only the speed V1 of the heating roller 43 to change the relative speed Vs between the heating roller 43 and the pressure roller 44. Therefore, the relationship between gloss level and relative speed Vs shown in FIG. 6 can be replaced with the relationship between gloss level and speed V1 of the heating roller 43 shown in FIG. 7. Then, the control unit 8 stores in the memory unit 9 speed information relating to the speed V1 of the heating roller 43 when the identification information 38 transferred to the recording medium 11 passes through the nip 45, and when the identification information 38 is specified by the user, the control unit 8 can specify the speed V1 of the heating roller 43 when the identification information 38 passes through the nip 45. The rate at which the speed V1 of the heating roller 43 is changed is, for example, within ±10% of the speed V2 of the pressure roller 44 as the reference.

[0055] Next, the operation of the control unit 8 will be described. As described above, when the characteristics of the recording medium 11, such as the type and basis weight of the recording medium 11, change, the glossiness of the image formed on the recording medium 11 changes. Therefore, in order to achieve the glossiness of the image formed on the recording medium 11 at the user's desired glossiness, it is necessary to perform control according to the characteristics of the recording medium 11. Therefore, when the control unit 8 of this embodiment detects that the recording medium 11 has been set on the trays 10a and 10b, it displays a tray setting screen on the display unit 6 of the operation panel 5, which prompts the user to input information about the recording medium 11 set on the trays 10a and 10b.

[0056] FIG. 8 shows an example of the tray setting screen G1. When the control unit 8 detects that a recording medium 11 has been set in the tray 10a or 10b, the control unit 8 displays the tray setting screen G1 as shown in FIG. 8(a) on the display unit 6. This screen G1 is a screen for setting the type of recording medium 11 set in the tray in which the recording medium 11 has been set, among the multiple trays 10a or 10b. That is, the screen G1 has a characteristic display area 101 that displays characteristics of the recording medium 11, such as the type and basis weight. This characteristic display area 101 displays information before the recording medium 11 was set in the tray 10a or 10b, for example. If the characteristics of the recording medium 11 set in the tray 10a or 10b match the characteristics displayed in the characteristic display area 101, the user can operate the OK button 104 to complete the tray setting.

[0057] Furthermore, if the user wishes to change the characteristics displayed in the characteristics display area 101, the user can operate a pull-down button 102 displayed adjacent to the characteristics display area 101. When the pull-down button 102 is operated, the control unit 8 transitions the screen G1 of the display unit 6 from FIG. 8(a) to FIG. 8(b). That is, the control unit 8 displays a pull-down menu 105 below the characteristics display area 101. This pull-down menu 105 displays a list of characteristics of the recording media 11 that have already been registered in the image forming apparatus 1. Therefore, if the pull-down menu 105 includes the characteristics of the recording media 11 set in the trays 10a and 10b, the user can select the characteristic to display the characteristic in the characteristics display area 101.

[0058] On the other hand, if the characteristics of the recording medium 11 set in the trays 10a and 10b are not included in the pull-down menu 105, the user returns to the screen G1 of FIG. 8(a) and then operates the new registration button 103. When the new registration button 103 is operated, the control unit 8 transitions the screen G1 of the display unit 6 from FIG. 8(a) to FIG. 8(c). That is, the control unit 8 displays a new registration screen 106. This new registration screen 106 is a screen on which the characteristics of the recording medium 11, such as the type and basis weight of the recording medium 11, can be input. After inputting the characteristics of the recording medium 11 in the new registration screen 106, the user can register the new characteristics in the image forming apparatus 1 by operating the OK button 107. Thereafter, the new characteristics are displayed in the pull-down menu 105. Therefore, the user can specify that the recording medium 11 set in the trays 10a and 10b has new characteristics by selecting new characteristics from the pull-down menu 105 and operating the OK button 104.

[0059] When the user sets the trays as described above, the control unit 8 generates tray information for the trays 10a and 10b and stores it in the storage unit 9. FIG. 9 is a diagram showing an example of tray information 60. The tray information 60 shown in FIG. 9 indicates that a recording medium 11 of type "coated paper" with a basis weight of "180 g" is set in "Tray 1," and that a recording medium 11 of type "coated paper" with a basis weight of "220 g" is set in "Tray 2." Therefore, by referring to this tray information 60, the control unit 8 can grasp the characteristics of the recording medium 11 when feeding the recording medium 11 from each of the multiple trays 10a and 10b.

[0060] When a user loads a new recording medium 11 in the tray 10a or 10b, the gloss adjustment mode is executed before executing a print job using the new recording medium 11. FIGS. 10 and 11 are diagrams showing example screens when the gloss adjustment mode is executed. First, when the user has finished setting the tray, the control unit 8 displays screen G2 shown in FIG. 10(a) on the display unit 6. This screen G2 is the initial screen of the image forming apparatus 1 and is a screen for performing operations related to a copy job. Therefore, screen G2 displays buttons 111 to 114 for setting various settings for the copy job. This screen G2 also displays a gloss adjustment button 115 for instructing the execution of the gloss adjustment mode. When a user loads a new recording medium 11 in the tray 10a or 10b, the user operates the gloss adjustment button 115 to operate the image forming apparatus 1 in the gloss adjustment mode before instructing the start of job execution.

[0061] When the gloss adjustment button 115 is operated, the control unit 8 displays a screen G3 shown in FIG. 10(b) on the display unit 6. Tray selection buttons 121 and 122 are displayed on this screen G3. This allows the user to select a tray on which the recording medium 11 whose gloss is to be adjusted in the gloss adjustment mode is set. Note that FIG. 10(b) illustrates a state in which the tray selection button 122 is selected. After selecting one tray, the user operates the OK button 123. When the OK button 123 is operated, the control unit 8 starts executing the gloss adjustment mode. Accordingly, the control unit 8 displays a screen G3 shown in FIG. 10(c) on the display unit 6, for example.

[0062] When the gloss adjustment mode begins, the control unit 8 feeds one sheet of recording medium 11 from the tray 10a or 10b specified by the user and transfers the image of the elongated rectangular pattern of each color and the identification information 38 onto the recording medium 11. Then, as the recording medium 11 onto which the toner 39 has been transferred passes through the fixing unit 4, the control unit 8 continuously changes the speed V1 of the heating roller 43 to form an image with continuously changing gloss on the recording medium 11. As a result, the recording medium 11 as shown in FIG. 5 is output onto the paper output tray 19.

[0063] When the ejection of the recording medium 11 is completed in the gloss adjustment mode, the control unit 8 displays a gloss setting screen G4 shown in FIG. 11 on the display unit 6. This gloss setting screen G4 is a screen on which the user can input a desired gloss level based on the identification information 38 printed on the recording medium 11. That is, the gloss setting screen G4 displays multiple buttons 131 corresponding to the identification information 38, and the user can specify the gloss level by selecting and operating the button 131 corresponding to the desired gloss level. Note that FIG. 11 illustrates a state in which a gloss level of "6" has been selected. After specifying the gloss level, the user operates the OK button 132. When the OK button 132 is operated, the control unit 8 identifies the gloss level specified by the user. Then, when a print job is executed by feeding paper from a tray specified by the user, the control unit 8 performs control so that an image with the gloss level specified by the user is produced.

[0064] 12 and 13 are flowcharts showing an example of a processing procedure performed by the control unit 8 when the gloss adjustment mode is executed. First, the control unit 8 determines whether the gloss adjustment button 115 has been operated by the user (step S10). If the gloss adjustment button 115 has not been operated (NO in step S10), the process proceeds to FIG. 13, where the processing by the control unit 8 ends. If the gloss adjustment button 115 has been operated (YES in step S10), the control unit 8 accepts a tray selection operation by the user (step S11). Then, when the user instructs execution of the gloss adjustment mode (YES in step S12), the control unit 8 reads the tray information 60 and determines the characteristics of the recording medium 11 set in the tray for which the gloss adjustment mode is to be executed (step S13). Based on the determination result, the control unit 8 sets the heating temperature of the heating roller 43 and the pressing force (nip pressure) of the pressure roller 44 in the fixing unit 4 (step S14). That is, because the appropriate heating temperature by the heating roller 43 and the appropriate pressing force by the pressure roller 44 differ depending on the type and basis weight of the recording medium 11, the control unit 8 sets a pressing temperature and pressing force appropriate for the characteristics of the recording medium 11. The control unit 8 also sets a process speed according to the characteristics of the recording medium 11 (step S15). Because the appropriate process speed also differs depending on the type and basis weight of the recording medium 11, the control unit 8 sets a process speed appropriate for the characteristics of the recording medium 11. The control unit 8 then sets the speed V2 of the pressure roller 44 to the process speed. This allows the conveyance speed of the recording medium 11 when passing through the fixing unit 4 to match the process speed.

[0065] Next, the control unit 8 starts feeding one sheet of recording medium 11 from the tray specified by the user (step S16), and when the recording medium 11 passes the position of the secondary transfer roller 16, an image of the same density is transferred onto the recording medium 11 in a long length along the conveyance direction of the recording medium 11 (step S17). At this time, the control unit 8 also transfers the identification information 38 onto the recording medium 11. As a result, an image such as that shown in FIG. 4 is formed on the recording medium 11.

[0066] Thereafter, when the leading edge of the recording medium 11 reaches the fixing unit 4 (step S18), the control unit 8 starts control to continuously change the speed of the heating roller 43, timing it so that the leading edge of the image of the same density passes through the nip 45 between the heating roller 43 and the pressure roller 44 (step S19). Then, when the identification information 38 passes through the nip 45, the control unit 8 records the identification information 38 and the speed V2 of the heating roller 43 at that time in association with each other, and stores them in the memory unit 9 (step S20). By repeatedly performing the process of step S20, the speed V1 of the heating roller 43 when the identification information 38 of "1" to "8" passes through the nip 45 is stored in the memory unit 9.

[0067] FIG. 14 is a diagram illustrating an example of information 61 stored in the memory unit 9 during execution of the gloss adjustment mode. As shown in FIG. 14, this information 61 is information recording the speed V1 of the heating roller 43 when each of the identification information 38 numbers "1" to "8" passes through the nip 45 between the heating roller 43 and the pressure roller 44, and is information in which the identification information 38 and the speed V1 are associated with each other. For example, when the process speed is 600 mm / s, the speed V1 of the heating roller 43 varies from a speed higher than the process speed to a speed lower than the process speed, and an image with a gloss level corresponding to each speed is formed on the recording medium 11. By recording such information 61 during execution of the gloss adjustment mode, when one of the numbers "1" to "8" assigned as the identification information 38 is designated, the control unit 8 can identify the speed V1 required to achieve the gloss level corresponding to the designated identification information 38.

[0068] Returning to the flowchart of FIG. 12, when the rear end of the recording medium 11 passes through the fixing unit 4 (YES in step S21) and the recording medium 11 is completely discharged from the image forming apparatus 1 (YES in step S22), the control unit 8 proceeds to the flowchart of FIG. 13. The control unit 8 then displays the gloss level setting screen G4 (see FIG. 11) on the display unit 6 (step S30) and accepts the user's selection of the gloss level (step S31). The control unit 8 identifies the gloss level specified by the user (step S32) and identifies the speed V1 of the heating roller 43 to reproduce the identified gloss level by referring to the information 61 shown in FIG. 14 (step S33). The control unit 8 then records information associating the identified gloss level with the speed V1 in the recording medium information 62 and stores it in the storage unit 9 (step S34).

[0069] FIG. 15 is a diagram showing an example of the recording medium information 62. As shown in FIG. 15, the recording medium information 62 is information that correlates characteristic information 62a of the recording medium 11 registered in the image forming apparatus 1, a gloss level 62b specified by the user, and speed information 62c indicating the speed V1 of the heating roller 43 required to achieve the gloss level 62b. By storing such recording medium information 62 in the storage unit 9, for example, when the recording medium 11 is set in the trays 10a and 10b, the control unit 8 can refer to the recording medium information 62 and display the above-mentioned pull-down menu 105 on the display unit 6. Furthermore, when the user selects the characteristic of the recording medium 11 from the pull-down menu 105, the control unit 8 can refer to the recording medium information 62 to specify the desired gloss level and can also specify the speed V1 of the heating roller 43 based on the speed information 62c associated with the gloss level.

[0070] Returning to the flowchart of Fig. 13, next, the control unit 8 sets the speed V1 of the heating roller 43 when feeding the recording medium 11 from the tray designated by the user and executing the print job, based on the speed V1 identified in step S33 (step S35). This completes the processing procedure of the control unit 8 in the gloss adjustment mode.

[0071] The gloss adjustment mode described above is not limited to being executed when a new recording medium 11 is loaded into trays 10a and 10b. That is, the user can cause image forming apparatus 1 to execute the gloss adjustment mode at any time. For example, because heating roller 43 and pressure roller 44 wear and deteriorate with use, the gloss of the image formed on recording medium 11 gradually changes over time. Furthermore, the gloss of the image formed on recording medium 11 also changes depending on changes in the environment (temperature and humidity) in which image forming apparatus 1 is installed. Therefore, the user can update the gloss and the speed V1 of heating roller 43 recorded in recording medium information 62 by specifying a recording medium 11 already registered in image forming apparatus 1 and executing the gloss adjustment mode. This eliminates the effects of wear and deterioration of heating roller 43 and pressure roller 44 and environmental changes, allowing the user to reproduce the desired gloss.

[0072] Next, FIG. 16 is a flowchart showing an example of a processing procedure performed by the control unit 8 when a print job is executed in the image forming apparatus 1. First, the control unit 8 determines whether or not a user has instructed the execution of a print job (step S40). If no instruction to execute a print job has been received (NO in step S40), the processing by the control unit 8 ends. If an instruction to execute a print job has been received (YES in step S40), the control unit 8 references the tray information 60 and detects the characteristics of the recording medium 11 set in the tray specified by the user (step S41). Then, the control unit 8 sets the process speed when the print job is executed based on the characteristics of the recording medium 11. In other words, the process speed when the print job is executed is determined according to the characteristics of the recording medium 11 used. At this time, the control unit 8 sets the speed V2 of the pressure roller 44 as the process speed (step S42).

[0073] Next, the control unit 8 refers to the recording medium information 62 (step S43) and determines whether a recording medium 11 that matches the characteristics of the recording medium 11 detected in step S41 is registered in the recording medium information 62 (step S44). That is, the control unit 8 determines whether the characteristic information 62a recorded in the recording medium information 62 includes information that matches the characteristics of the recording medium 11. For example, if the gloss adjustment mode has already been executed for the recording medium 11 used in the print job, information about that recording medium 11 is registered in the recording medium information 62. However, if the gloss adjustment mode has not yet been executed for the recording medium 11 used in the print job, information about that recording medium 11 is not registered in the recording medium information 62.

[0074] If a recording medium 11 with the same characteristics is registered in the recording medium information 62 (YES in step S44), the control unit 8 reads out the speed V1 of the heating roller 43 recorded as the speed information 62c from the recording medium information 62 (step S45), and sets the read-out speed V1 as the speed V1 of the heating roller 43 when the print job is executed (step S46). As a result, the glossiness of the image formed on the recording medium 11 becomes the glossiness specified in advance by the user.

[0075] On the other hand, if a recording medium 11 with the same characteristics is not registered in the recording medium information 62 (NO in step S44), the control unit 8 sets the speed V1 of the heating roller 43 to the process speed (step S47). In other words, since the gloss level desired by the user has not been set for the recording medium 11 used in the print job, the control unit 8 sets the speed V1 of the heating roller 43 to a state that matches the speed V2 of the pressure roller 44 when the print job is executed. As a result, the gloss level of the image formed on the recording medium 11 becomes the standard gloss level for the image forming apparatus 1.

[0076] Thereafter, the control unit 8 starts executing the print job (step S48). That is, the control unit 8 feeds the recording medium 11 from the tray 10a or 10b specified by the user and controls the image forming unit 3 to transfer an image based on the image data to be printed onto the recording medium 11. Then, when the recording medium 11 with the transferred image passes through the fixing unit 4, the control unit 8 rotates the pressure roller 44 at the process speed and rotates the heating roller 43 at the speed V1 set in step S46 or S47. When the heating roller 43 is rotated at the speed V1 set in step S46, an image with a glossiness previously specified by the user is formed on the recording medium 11 output by the print job. Then, when the execution of the print job is completed (YES in step S49), the processing procedure by the control unit 8 ends.

[0077] As described above, the image forming apparatus 1 of this embodiment has a glossiness adjustment mode in addition to a normal operation mode for executing normal print jobs, etc. In this glossiness adjustment mode, the image forming apparatus 1 changes the relative speed Vs between the heating roller 43 and the pressure roller 44 while the recording medium 11 passes through the nip 45 between the heating roller 43 and the pressure roller 44 to form and output an image with varying glossiness on the same surface of the recording medium 11. This allows the user to check the recording medium 11 output from the image forming apparatus 1 in the glossiness adjustment mode and set the desired glossiness for the image forming apparatus 1. In particular, the image forming apparatus 1 of this embodiment has the advantage of easily controlling the change in glossiness because it forms an image with varying glossiness on a single recording medium 11 by changing the relative speed Vs between the heating roller 43 and the pressure roller 44. This makes it possible to easily and reliably form images with different glossiness on a single recording medium 11, which was previously difficult.

[0078] (Variation) Although a preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be applied.

[0079] For example, in the above embodiment, an example was given in which operation in the glossiness adjustment mode is performed when a user instructs execution of the glossiness adjustment mode. However, the glossiness adjustment mode is not limited to being executed in response to a user instruction, and can also be executed automatically. For example, when a new recording medium 11 is set in tray 10a or 10b of image forming apparatus 1, image forming apparatus 1 may automatically execute the glossiness adjustment mode. Furthermore, image forming apparatus 1 may automatically execute the glossiness adjustment mode when images have been formed on a predetermined number of recording media 11 or when an environmental change is detected.

[0080] Furthermore, in the above embodiment, as an example of changing the relative speed Vs between the speed V1 of the heating roller 43 and the speed V2 of the pressure roller 44, the speed V2 of the pressure roller 44 is maintained at the process speed, and the speed V1 of the heating roller 43 is changed. However, this is not limited to this, and when changing the relative speed Vs, both the speed V1 of the heating roller 43 and the speed V2 of the pressure roller 44 may be changed. Alternatively, the speed V1 of the heating roller 43 may be maintained constant, and only the speed V2 of the pressure roller 44 may be changed.

[0081] In the above embodiment, an example was described in which the relative speed Vs between the heating roller 43 and the pressure roller 44 is continuously changed when the recording medium 11 onto which the toner 39 has been transferred passes through the nip 45 between the heating roller 43 and the pressure roller 44 in the gloss adjustment mode. However, the manner in which the relative speed Vs is changed is not necessarily limited to a continuous change. For example, the relative speed Vs between the heating roller 43 and the pressure roller 44 may be changed in steps. However, when changing the relative speed Vs in steps, it is preferable to control it so that the gloss does not change in steps at the positions where the above-mentioned identification information 38 "1" to "8" is printed.

[0082] In the above embodiment, the heating rotor 41 is configured by the heating roller 43. However, the heating rotor 41 is not limited to being configured by the heating roller 43. For example, the heating rotor 41 may include a fixing belt stretched between a plurality of rollers, and the fixing belt may be joined to the pressure roller 44 to form the nip 45. In this case, the fixing belt performs the same function as the heating roller 43 described above.

[0083] The same applies to the pressure rotating body 42. That is, the pressure rotating body 42 is not limited to being constituted by the pressure roller 44 described above, but may be one that includes a pressure belt stretched between a plurality of rollers, that forms a nip 45 by joining the pressure belt to the heating roller 43, and that applies a pressure contact force by pressing the pressure belt toward the heating roller 43.

[0084] Furthermore, in the above embodiment, an example has been given in which the user manually inputs the characteristics of the recording medium 11 into the image forming apparatus 1. However, the characteristics of the recording medium 11 are not limited to those manually input by the user into the image forming apparatus 1. For example, the image forming apparatus 1 can automatically detect the characteristics of the recording medium 11 by installing media sensors in the trays 10a and 10b or the conveyance path 14. Therefore, a configuration in which the characteristics of the recording medium 11 are automatically detected by such media sensors may be adopted.

[0085] In the above embodiment, an example was described in which, in the gloss adjustment mode, images of long rectangular patterns in each of the colors Y, M, C, and K are transferred onto the recording medium 11, thereby outputting a recording medium 11 in which the user can check the glossiness of each color. However, the gloss adjustment mode is not limited to color printing using Y, M, C, and K, and monochrome printing using only K is also possible. For example, the image forming apparatus 1 may be provided with a color printing mode and a monochrome printing mode. The color printing mode is set when printing photographic images, etc., and the monochrome printing mode is set when printing text images, etc. For photographic images, etc., a high gloss level is preferable, while for text images, etc., a low gloss level is sometimes preferable from the standpoint of readability. Therefore, it is preferable that the gloss adjustment mode be able to adjust the gloss level separately for the color printing mode and the monochrome printing mode.

[0086] In the above embodiment, the image forming apparatus 1 is configured as an MFP having multiple functions such as a copy function, a scan function, and a print function. However, the image forming apparatus 1 is not limited to being configured as an MFP. For example, the image forming apparatus 1 may be a device having only a print function. [Explanation of symbols]

[0087] 1. Image forming device 3 Image forming unit 4 Fixing section 8 Control Unit 9 Storage section 11 Recording media 38 Identification Information 41 Heating Rotor 44 Pressurized Rotating Body 45 Nip

Claims

1. An image forming apparatus in which a nip is formed between a heating rotator and a pressure rotator, and a recording medium onto which toner has been transferred and which is conveyed is heated and pressurized at the nip, thereby fixing the toner to the recording medium, a glossiness adjustment mode in which, while the recording medium is passing through the nip, the relative speed between the heating rotor and the pressure rotor is changed to form and output an image with a varying glossiness within the same surface of the recording medium; The image forming apparatus is characterized in that the gloss level adjustment mode continuously changes the relative speed between the heating rotator and the pressure rotator.

2. 2. The image forming apparatus according to claim 1, wherein the gloss level adjustment mode keeps the speed of the pressure rotating member constant and changes the speed of the heating rotating member.

3. An image forming apparatus in which a nip is formed between a heating rotator and a pressure rotator, and a recording medium onto which toner has been transferred and which is conveyed is heated and pressurized at the nip, thereby fixing the toner to the recording medium, a glossiness adjustment mode in which, while the recording medium is passing through the nip, the relative speed between the heating rotor and the pressure rotor is changed to form and output an image with a varying glossiness within the same surface of the recording medium; The image forming apparatus is characterized in that, in the gloss level adjustment mode, the speed of the pressure rotating member is kept constant at the conveying speed of the recording medium, and the speed of the heating rotating member is changed.

4. An image forming apparatus in which a nip is formed between a heating rotator and a pressure rotator, and a recording medium onto which toner has been transferred and which is conveyed is heated and pressurized at the nip, thereby fixing the toner to the recording medium, an image forming unit that transfers the toner onto the recording medium; a glossiness adjustment mode in which, while the recording medium is passing through the nip, the relative speed between the heating rotor and the pressure rotor is changed to form and output an image with a varying glossiness within the same surface of the recording medium; The image forming apparatus is characterized in that, in the gloss level adjustment mode, the image forming unit forms an image of uniform density along the conveyance direction of the recording medium.

5. 5. The image forming apparatus according to claim 4, wherein the image forming unit prints identification information indicating a gloss level along a conveyance direction of the recording medium when forming an image of the same density on the recording medium.

6. a control unit that sets the gloss level when a print job is executed; Equipped with The image forming apparatus according to claim 5, wherein when the identification information printed on the recording medium is specified by a user, the control unit sets the gloss level at the time of executing the print job based on the specified identification information.

7. a storage unit that stores, in the gloss level adjustment mode, speed information of the heating rotator and the pressure rotator when the identification information passes through the nip in association with the identification information; Further provided with The image forming apparatus according to claim 6, characterized in that, when the identification information printed on the recording medium is specified by a user, the control unit reads out the speed information associated with the specified identification information from the memory unit and sets the speed when executing a print job.

8. the storage unit stores characteristic information indicating characteristics of the recording medium used in the gloss level adjustment mode in association with the identification information, The image forming apparatus according to claim 7, characterized in that the control unit sets the speed when executing the print job based on the speed information read from the memory unit when the characteristics of the recording medium used when executing the print job match the characteristics of the recording medium indicated by the characteristic information.

9. A control method for an image forming apparatus in which a nip is formed between a heating rotator and a pressure rotator, and a recording medium onto which toner has been transferred and which is conveyed is heated and pressurized at the nip, thereby fixing the toner to the recording medium, comprising: operating the image forming apparatus in a glossiness adjustment mode in which, while the recording medium is passing through the nip, a relative speed between the heating rotor and the pressure rotor is changed to form and output an image with a varying glossiness within the same surface of the recording medium; A control method characterized in that, in the gloss level adjustment mode, the relative speed between the heating rotor and the pressure rotor is continuously changed.

10. 10. The control method according to claim 9, wherein in the gloss level adjustment mode, the speed of the pressure rotating member is kept constant and the speed of the heating rotating member is changed.

11. A control method for an image forming apparatus in which a nip is formed between a heating rotator and a pressure rotator, and a recording medium onto which toner has been transferred and which is conveyed is heated and pressurized at the nip, thereby fixing the toner to the recording medium, comprising: operating the image forming apparatus in a glossiness adjustment mode in which, while the recording medium is passing through the nip, a relative speed between the heating rotor and the pressure rotor is changed to form and output an image with a varying glossiness within the same surface of the recording medium; A control method characterized in that, in the gloss level adjustment mode, the speed of the pressure rotating member is kept constant at the conveying speed of the recording medium, and the speed of the heating rotating member is changed.

12. A control method for an image forming apparatus in which a nip is formed between a heating rotator and a pressure rotator, and a recording medium onto which toner has been transferred and which is conveyed is heated and pressurized at the nip, thereby fixing the toner to the recording medium, comprising: operating the image forming apparatus in a glossiness adjustment mode in which, while the recording medium is passing through the nip, a relative speed between the heating rotor and the pressure rotor is changed to form and output an image with a varying glossiness within the same surface of the recording medium; A control method comprising forming an image of the same density along the conveyance direction of the recording medium in the gloss level adjustment mode.

13. 13. The control method according to claim 12, wherein when an image of the same density is formed on the recording medium, identification information indicating the glossiness is printed along the conveyance direction of the recording medium.

14. 14. The control method according to claim 13, wherein, when the identification information printed on the recording medium is designated by a user, the gloss level at the time of executing a print job is set based on the designated identification information.

15. The control method described in claim 14, characterized in that in the gloss adjustment mode, speed information of the heating rotor and the pressure rotor when the identification information passes through the nip is stored in a predetermined memory unit in correspondence with the identification information, and when the identification information printed on the recording medium is specified by a user during execution of a print job, the speed information corresponding to the specified identification information is read from the memory unit and a speed setting is performed during execution of the print job.

16. characteristic information indicating the characteristics of the recording medium used in the gloss level adjustment mode is further associated with the identification information and stored in the storage unit; The control method according to claim 15, characterized in that, when the characteristics of the recording medium used when executing the print job match the characteristics of the recording medium indicated by the characteristic information, the speed setting when executing the print job is performed based on the speed information read from the memory unit.

Images